@mixin flex($direction: between) {
  display: flex;
  align-items: center;
  @if $direction == start {
    justify-content: flex-start;
  } @else if $direction == end {
    justify-content: flex-end;
  } @else if $direction == around {
    justify-content: space-around;
  } @else if $direction == between {
    justify-content: space-between;
  }
}